1. Field of the Invention
This invention relates to ion measuring devices for measuring positive and negative ions as charged gas molecules or fine particles present in air.
2. Prior Art
Up to date, negative ions which are capable of giving good influence to the living body, such as healthy effect of preventing oxidization of the human body, effect of holding freshness of foodstuff and deodorizing effect, and also positive ions which provide converse action to negative ions, are attracting attention, and various types of ion measuring devices for measuring negative and/or positive ions are present.
In the prior art ion measuring devices, however, a positive ion measuring unit for measuring positive ions and a negative ion measuring unit for measuring negative ions are present independently, or a single ion measuring unit has independent negative and positive ion measuring parts. Therefore, the prior art ion measuring devices are inevitably large in scale and expensive. Besides, although air ions require fine and sophisticated measuring conditions, it has been very doubtful that negative and positive ion measurement values obtained by different measuring systems are in right correlation to one another. In the prior art, an ion measuring device is also present, in which the negative and positive ion measurements are made in a single system by switching one over to the other. In this case, however, the switching of the xe2x80x9cnegativexe2x80x9d and xe2x80x9cpositivexe2x80x9d measurements is done manually, and it is necessary to manually discharge a charge collector in a measuring part whenever the switching is done. Therefore, the operation is cumbersome, and the measurement requires great labor and time.
The invention has an object of providing an ion measuring device, which can accurately and readily measure both positive and negative ion data and be realized as a reduced size and thickness structure. To attain this object, an ion measuring device is provided, which comprises an ion detecting means including a charge collector electrode disposed in an air passage with an air passing member disposed therein and capable of collecting ions in air and repelling electrodes disposed to face the charge collector electrode, a measurement computation means for measuring charge on the charge collector electrode and executing computation processing on the measured charge to obtain data representing the number of measured positive and negative ions per unit time and unit volume, a charging means including a switching means for switching the positive and negative polarities of charging the repelling electrodes such that the repelling electrodes are charged to the same polarity of measurement subject ions, and a discharging means for discharging the charge collector electrode at time intervals corresponding to the timings of switching by the switching means.